ipv6: add flowinfo for tcp6 pkt_options for all cases

The current implementation of IPV6_FLOWINFO only gives a
result if pktoptions is available (thanks to the
ip6_datagram_recv_ctl function).
It gives inconsistent results to user space, sometimes
there is a result for getsockopt(IPV6_FLOWINFO), sometimes
not.

This patch add rcv_flowinfo to store it, and return it to
the userspace in the same way than other pkt_options.

Signed-off-by: Florent Fourcot <florent.fourcot@enst-bretagne.fr>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c56c350324e4..0b2ebfbbe0f4 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -201,6 +201,7 @@ struct ipv6_pinfo {
         __u8                    min_hopcount;
         __u8                    tclass;
         __u8                    rcv_tclass;
+        __be32                  rcv_flowinfo;
 
         __u32                   dst_cookie;
         __u32                   rx_dst_cookie;
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 1c6ce3119ff8..c2db1df46385 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -1034,6 +1034,10 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
                                 int hlim = np->mcast_hops;
                                 put_cmsg(&msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
                         }
+                        if (np->rxopt.bits.rxflow) {
+                                int flowinfo = np->rcv_flowinfo;
+                                put_cmsg(&msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
+                        }
                 }
                 len -= msg.msg_controllen;
                 return put_user(len, optlen);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0740f93a114a..79a196369558 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1136,6 +1136,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
                 newnp->mcast_oif   = inet6_iif(skb);
                 newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
                 newnp->rcv_tclass  = ipv6_get_dsfield(ipv6_hdr(skb));
+                newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
 
                 /*
                  * No need to charge this sock to the relevant IPv6 refcnt debug socks count
@@ -1216,6 +1217,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
         newnp->mcast_oif  = inet6_iif(skb);
         newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
         newnp->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
+        newnp->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(skb));
 
         /* Clone native IPv6 options from listening socket (if any)
 
@@ -1427,6 +1429,8 @@ ipv6_pktoptions:
                         np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
                 if (np->rxopt.bits.rxtclass)
                         np->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(opt_skb));
+                if (np->rxopt.bits.rxflow)
+                        np->rcv_flowinfo = ip6_flowinfo(ipv6_hdr(opt_skb));
                 if (ipv6_opt_accepted(sk, opt_skb)) {
                         skb_set_owner_r(opt_skb, sk);
                         opt_skb = xchg(&np->pktoptions, opt_skb);